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A.Diederich– International University Bremen – USC – MMM Spring Sound of a physical stimulus: pressure changes in the air

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A.Diederich– International University Bremen – USC – MMM Spring Sound waves –are longitudinal waves. –are alternations of rarefaction and compression of an elastic medium (such as water, air, or walls) in which they travel. –are created by rapid movement of a source in mechanical contact with this medium. –can be transmitted for great distances. –cannot pass through a vacuum. –The speed of sound varies according to the medium in which it travels.

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A.Diederich– International University Bremen – USC – MMM Spring

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6 –Wavelength ( ): distance from one peak of the wave to the next –Cycle: the completion of a full sequence of air rarefaction and compression –Frequency (f): number of cycles a sound wave completes in one second –Hertz (Hz): unit (cycles per second) used to measure frequency of sound waves – = v/f (v: velocity (m s -1 )) –Pressure amplitude: measure of the size of the variation in air pressure caused by a sound wave

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A.Diederich– International University Bremen – USC – MMM Spring –Phase: the particular point in the compression- rarefaction cycle of sound wave at one instant of time –Phase (in phase; out of phase; how much they are out of phase is expressed in terms of phase angle  )

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A.Diederich– International University Bremen – USC – MMM Spring Additive synthesis –Fundamental frequency (or first harmonic): starting frequency for a complex sound –Harmonics: pure tones, each of which has a frequency that is a multiple of the fundamental